Rossby waves in rapidly rotating Bose-Einstein condensates

TL;DR

This paper predicts a new Rossby-like collective mode in rapidly rotating Bose-Einstein condensates, driven by Coriolis forces, with unique propagation characteristics and implications for understanding quantum fluid dynamics.

Contribution

It introduces a novel Rossby wave analog in Bose-Einstein condensates under rapid rotation, deriving a nonlinear equation accounting for pressure and trap anharmonicity effects.

Findings

Rossby-like waves have negative phase speed.

Waves propagate opposite to the rotation direction.

Comparison with Thomas-Fermi approximation results.

Abstract

We predict and describe a new collective mode in rotating Bose-Einstein condensates, which is very similar to the Rossby waves in geophysics. In the regime of fast rotation, the Coriolis force dominates the dynamics and acts as a restoring force for acoustic-drift waves along the condensate. We derive a nonlinear equation that includes the effects of both the zero-point pressure and the anharmonicity of the trap. It is shown that such waves have negative phase speed, propagating in the opposite sense of the rotation. We discuss different equilibrium configurations and compare with those resulting from the Thomas-Fermi approximation.